Project Summary/Abstract Carcinoma of the pancreas, or pancreatic cancer (PC), is the third leading cause of cancer-related death in the US. Despite recent advances in the current treatments that include surgery, radiation therapy, chemo- and immunotherapy, the 5-year survival rate is as low as 9%. The long-term goal of this project is to develop a first-in-class, efficient and well tolerable therapy for PC to be used standalone or with standard chemo- and/or immune checkpoint blockade (ICB) treatments as induction and/or maintenance therapy. In PC patients, overexpression of TREM-1 correlates with poor survival, implicating TREM-1 as a new target. Current TREM-1 blockers all attempt to block binding of uncertain ligand(s) to TREM-1. To reduce risk of failure in the clinic, we developed a ligand-independent TREM-1 inhibitory peptide GF9 that can be formulated into macrophage-specific lipopeptide complexes (LPC) to improve its half-life and targeting. In Phase I, we showed that: 1) In suppressing tumor growth and improving survival, TREM-1 blockade using GF9-LPC in PC xenografts is as effective as a standard chemo: gemcitabine (GEM)+nab-paclitaxel (PTX) combo, and 2) addition of GF9-LPC to GEM+nab-PTX sensitizes the tumor to chemo and triples survival rate of mice. Mechanistically, in PC xenografts, GF9-LPC reduces tumor-associated macrophage (TAM) infiltration and serum level of CSF1. As shown by others, in mice with hepatocellular carcinoma, blocking TREM-1+ TAMs by GF9 reverses immunosuppression and overcomes anti-PDL1 resistance. The goal of this project is to further develop GF9 therapy for PC to be used as an induction/maintenance therapy alone or with first-line standard chemo treatments (GEM+nab-PTX) and/or ICB (anti-PD1/PDL1). Phase II aims are to: 1) generate and test rationally designed manufacturing friendly GF9 sequence- based formulations with favorable pharmacokinetic profile and high efficacy in vivo and select the lead (sub-aim ? develop an assay to analyze GF9 in blood in PK studies), 2) test the lead in combination with GEM+nab-PTX in xenograft and syngeneic mouse models of PC, 3) test the lead in combination with anti- PD1/PDL1 in syngeneic mouse models of PC, and 4) test the lead in the non-clinical toxicology studies. Histology/IHC studies will be performed to analyze intratumoral macrophage infiltration as well as angiogenesis, tumor cell proliferation and death. Cytokines including CSF-1 will be analyzed. Follow-up Phase IIb will include other administration and combination (eg, radiation+GF9; anti-CSF-1R+ GF9) regimen, TOX, ADME, CMC and other IND-enabling studies. Final manufacturing friendly product will represent safe and stable PC therapy. Its anticipated safety is supported by good tolerability of SignaBlok's GF9 sequence-based formulations by long term-treated healthy, cancer and arthritic mice. Prototypes of SignaBlok's LPC were safe and well tolerated in clinical trials. TREM-1 blockade using peptide LR12 by SignaBlok's top competitor (Inotrem, France) was safe and well tolerated in healthy and septic subjects.